According to an article in Network World, McGraw-Hill uses Google Book Search on its Web site in spite of the fact that it is suing Google over the product.
How can this be? McGraw-Hill participates in the Google Book Search Partner Program, which gives publishers control over access to their digitized books, but, at the same time, it objects to Google’s efforts to scan and make available copies of its books in libraries without its permission.
Source: Perez, Juan Carlos. "Google’s Book Search Available in Publisher Sites." Network World, 1 June 2007.